Weeds

Weeds pose a significant threat to economic development and the natural resources of the Tiwi Islands. They have been a feature of the Tiwi landscape for many years and are mostly confined to communities and other disturbed land. During the 1960s and 1970s weeds were introduced to the Islands when the Australian Government was undertaking forestry research trials. Since then, increased traffic from the mainland has resulted in more species being accidentally introduced to the Islands.

Weeds of National Significance (WoNS) are a list of Australia’s 32 most problematic invasive plant species. The Australian Government declared them based on their high invasiveness, potential for spread, and severe economic, environmental, and social impacts. WoNS on the Tiwi Islands include Lantana (Lantana camara), Mimosa (Mimosa pigra) and Gamba Grass (Andropogon gayanus).

Weeds found on the Tiwis

Trees

• Neem (Azadirachta indica)

Shrubs

• Fringed Spider Flower (Cleome rutidosperma)

• Bellyache Bush (Jatropha gossypiifolia)

• Lantana (Lantana camara)

• Mimosa (Mimosa pigra)

• Snakeweed (Stachytarpheta spp.)

• Siam Weed (Chromolaena odorata)

Vines

• Rangoon Creeper (Combretum indicum)

• Ornamental Rubber Vine (Cryptostegia madagascariensis)

Grasses

• Gamba Grass (Andropogon gayanus)

• Mission Grass (Cenchrus polystachios)

• Guinea Grass (Megathyrsus maximus)

The Northern Territory (NT) Weeds Management Act 2001 is the primary legislation to protect the Territory's economy, community, and environment from the adverse impacts of weeds. It places the legal responsibility for weed control directly on landowners.

Tiwi Islands weeds listed according to their Class under the NT Act include:

Class A: To be eradicated

• Bellyache Bush (Jatropha gossypiifolia)

• Mimosa (Mimosa pigra)

• Ornamental Rubber Vine (Cryptostegia madagascariensis)

• Gamba Grass (Andropogon gayanus)

Class B: Growth and spread controlled

• Neem (Azadirachta indica)

• Lantana (Lantana camara)

• Snakeweed (Stachytarpheta spp.)

• Mission Grass (Cenchrus polystachios)

What action is being taken?

Weed management on the Tiwi Islands is undertaken by the Tiwi Rangers and the Tiwi Land Council. Unlike many other areas in the Northern Territory, there is real potential to eradicate many invasive weeds from the Tiwi Islands as the surrounding sea acts as a highly effective natural barrier. Visitors to the Islands are asked to carefully checking luggage, freight and vehicles to reduce further accidental introduction and spread of plant fragments and seeds.

Further Information: Tiwi Resources admin@tiwiresources.com.au